Filling Device for the Volumetric Metering of Powder

ABSTRACT

The invention relates to a filling device ( 1 ) for the volumetric metering of powder ( 2 ), particularly a powdery pharmaceutical. The filling device comprises a metering container ( 3, 4 ) having an inner chamber ( 5 ) and a peripheral edge ( 8, 9 ) around a filling opening ( 6, 7 ) of the metering container ( 3, 4 ), a planar retaining device ( 10 ), which is pervious to air, but impermeable to the powder ( 2 ), and covers the filling opening ( 6, 7 ) and the edge ( 8, 9 ) when filling the metering container ( 3, 4 ), a filling pipe ( 11 ), which is guided through the retaining device ( 10 ) and opens into the inner chamber ( 3 ) when filling the metering container ( 3, 4 ), and means for generating a pressure differential on the retaining device ( 10 ).

The invention concerns a filling device for volumetric metering ofpowder, in particular for metering a powdery pharmaceutical.

Small powder quantities, in particular small quantities of a powderypharmaceutical, for example, for pulmonary or transdermaladministration, must be metered and packaged in individual doses of afew milligrams or even micrograms suitable for the user. Such meteringby weighing is difficult so that frequently in such applicationsituations a volumetric metering is done.

A known form of volumetric metering is realized by means of a so-calledmetering roller where a cylindrical roller is provided with one orseveral rows of calibrated metering chambers. The latter are filled withpowder by using vacuum. Subsequently, the roller with the filledmetering chambers is rotated into an upside down position in which thepowder is blown out of the metering chambers into the providedindividual containers. The metering precision that is achievable in thisway is precise enough for most application situations. However, theprocessing speed is not always satisfactory. Moreover, it is requiredthat the containers are aligned in a row with one another whichalignment corresponds to the row of the metering chambers of the roller.Deviating container arrangements, for example, a circular arrangement,cannot be filled with the metering roller or filled only withdifficultly.

EP 0 474 466 61 discloses a device and a method for filling meteringcontainers wherein the metering containers are formed directly by thestorage containers in the form of blisters provided for use by the user.The blisters have a predefined individual volume and are immersed upsidedown into a powder thereby being completely filled with the quantity ofits predetermined volume. Volumetric metering of the powder and fillingof the blisters are done in a single working step. After completion ofmetering and filling, the blisters are sealed and are then ready to use.

The aforementioned form of filling enables potentially high processingspeeds. However, for a reliable metering, a satisfactory filled powderbed must be made available permanently, wherein, after completion of thefilling process, possibly significant residual quantities of usuallyrather expensive powder will remain. Filling in particular of smallercharges can therefore be uneconomical. Moreover, it has been observedthat in general very finely dispersed powder that has the tendency toform agglomerates will adhere, as a result of the immersion process, onthe sealing surfaces of the blisters so that a complex cleaning of thesealing surfaces before application of the sealing film is required.Stripping the sealing surfaces with a doctor blade not always leads tothe desired cleaning effect and, moreover, a falsification of themetered amount as well as an undesirable compaction of the powder mayresult. A reliable seal-tight sealing action of the container isdifficult.

The invention has the object to provide a filling device for volumetricmetering of powder, in particular of a powdery pharmaceutical, withincreased economic efficiency and processing safety.

This object is solved by a filling device with the features of claim 1.

A filling device for volumetric metering of powder, in particular of apowdery pharmaceutical, is proposed that has a metering container withan interior and with a rim that extends circumferentially about a fillopening of the metering container, a flat permeable retaining devicethat is however impermeable for the powder which retaining device uponfilling of the metering container covers the fill opening and the rim, afilling conduit that passes through the retaining device and that, whenfilling the metering container, opens into the interior, as well asmeans for generating a pressure differential at the retaining device.

In the method according to the invention, the aforementioned arrangementenables an economic filling and volumetric metering of powder with highprocessing speed and high processing safety. By means of the pressuredifferential that exists at the retaining device with relativelyincreased pressure in the interior of the metering container and withreduced pressure at the opposite exterior side of the retaining device,the powder is introduced through the filling conduit into the interiorof the metering container and retained therein by the retaining device.The pressure differential is maintained at least until the interior ofthe metering container has been completely filled with the powder. Thevolume that is defined or delimited by the shape of the meteringcontainer and by the retaining device determines precisely the volume ofthe powder quantity to be filled in. Since the retaining device not onlycovers the fill opening but also the rim of the metering container, nocontamination of the rim with powder occurs. After removal of theretaining device no post-processing of the rim and the powder surface,for example, by stripping with a doctor blade, is required. Therespective metering container can be filled to the rim with highprocessing speed and high metering precision and, if needed, can besealed without any further intermediate steps.

In a preferred further embodiment the retaining device is embodied as adiaphragm with gas passages that pass through the diaphragm and areseparate from one another. The separation of the gas passages from oneanother in the direction of the plane of the diaphragm enables flowthrough the diaphragm transversely to the diaphragm surface without flowoccurring in the direction of the membrane surface. By means of thediaphragm that covers the rim area of the metering container, no foreignair can be sucked in at the rim areas in the lateral direction when apressure differential is present; this contributes to increased meteringprecision and increased processing speed.

In an advantageous embodiment the retaining device is elasticallydeformable transversely to its surface wherein the filling conduit isconnected fixedly to the retaining device. A filling level control ofthe powder in the interior of the metering container by lifting orlowering the filling conduit by utilizing the elastic yielding action ofthe retaining device is provided. The filling conduit that is embodied,for example, as an immersion tube can be inserted into or removed fromthe interior of the metering container, as needed, as the retainingdevice is resting against the container. Density fluctuations ofdifferent powder charges, volume fluctuations of the individual meteringcontainers or the like can be compensated in a simple way. In any case,an adaptation of the filling volume to the respective need is possiblein a simple way.

Alternatively, it can be expedient that the filling conduit is guided inthe retaining device so as to be slidable in its longitudinal directionwherein a filling level control of the powder in the interior for themetering container is provided by sliding in or pulling out the fillingconduit in the through passage of the retaining device. As in the caseof the elastic deformation of the retaining device, an immersion of thefilling conduit to a greater or lesser extent also leads to a fillinglevel that is more or less distinct so that, as needed, an adaptation ofthe degree of filling or of the metered powder volume to the respectiveneed is possible.

In a preferred embodiment, the retaining device covers continuouslyseveral metering containers. With a single diaphragm or film or thelike, several containers can be filled at the same time; this increasesthe filling throughput and thus the economic efficiency of thearrangement significantly. In this connection, the relative orientationof the individual metering containers to one another is not important oronly important to a limited extent. This enables a need-oriented, almostrandom relative arrangement of the metering containers, for example, ina matrix or circular shape wherein, however, other client-specificarrangements can be covered also without problem. All arrangements canbe filled more or less at the same time which contributes to increasedeconomic efficiency.

In a preferred embodiment, several filling conduits per meteringcontainer are passed through the retaining device. In this way, it ispossible to fill to the rim also containers with irregular contour.Client-specific predetermined container shapes, for example, withcorners or angles, can be filled with high processing safety withoutleaving any gaps by an adapted arrangement of the filling conduits.

Preferably, the retaining device is pressed circumferentially againstthe rim of the metering container by means of a pressing frame,particularly an elastic pressing frame that is contour-flush relative tothe rim of the metering container. On the one hand, a reliable sealingaction of the container interior is provided wherein the elasticconfiguration of the pressing frame compensates dimensional tolerancesin the area of the container rim. On the other hand, it is ensured thatthe retaining device freely covers the fill opening completely up to therim so that no dead space is produced. Even in the rim areas a gap-freepowder filling is provided which also contributes to the precision ofthe volumetric metering. Alternatively, it can be expedient that theretaining device is pressed circumferentially against the rim of themetering container by means of a flat pressing plate that covers the rimand the fill opening and is air-permeable and in particular elastic. Inaddition to the aforementioned advantages in connection with the elasticpressing frame in this way it is also achieved that the arrangement isnot tied to the format of the respective metering container. Withoutchanges or adaptation of the pressing plate to the contour of themetering container to be filled, respectively, filling work withchanging container shapes can be performed.

The aforementioned means for generating the pressure differential at theretaining device can be, for example, an overpressure source by means ofwhich the powder is blown through the filling conduit into the interiorof the metering container, respectively. In a preferred furtherembodiment, for the formation of the means for generating the pressuredifferential, at the side of the retaining device facing away from themetering container a chamber is arranged that is open toward theretaining device but otherwise is closed wherein the chamber has aconnector to a vacuum source. For the actual filling process, thechamber is connected to the vacuum source so that vacuum is generatedtherein. In the powder reservoir there is atmospheric pressure so that,as a result, the desired pressure differential is generated at theretaining device. This causes the powder from the reservoir to be suckedin through the filling conduit into the container interior. Meanwhile,air flows through the retaining device without the powder particlesbeing able to penetrate the retaining device. With simple means, acomplete filling of the container interior is ensured.

In addition, it may be expedient that the retaining chamber is providedwith a connection to an overpressure source. After completed filling, ashort reverse flushing can be performed, as needed, with which powderadhering to or partially sucked into the retaining device is cleanedoff.

In a preferred embodiment, the metering container is a containerprovided for a later sealing action. Without further intermediatemeasures, metering of the powder directly in the storage container takesplace. The coverage of its rims with the retaining device keeps themfree of powder so that without further cleaning measures a directsealing action, for example, by gluing or welding a film thereon, can bedone. Alternatively, it can be expedient that the metering container isa metering chamber that is provided for future filling of a storagecontainer. This is primarily of interest when the metering volume is setto deviate significantly from the volume of the storage container. Inany case, a great processing speed with high processing safety andexcellent economic efficiency is provided.

In general, the presence of a powder bed is no longer needed. Instead,the powder is sucked in through the filling conduit from a storagecontainer or a distribution conduit. The latter can be emptiedcompletely during the run of the operation so that cost-intensiveresidual quantities must not be accepted.

Embodiments will be explained in the following with the aid of thedrawing in more detail. It is shown in:

FIG. 1 in a schematic longitudinal section illustration a filling deviceaccording to the invention with a metering container that is covered bya diaphragm, a filling conduit passing through the diaphragm, and avacuum chamber arranged on the exterior side of the diaphragm;

FIG. 2 a schematic transverse section illustration of the diaphragmaccording to FIG. 1 with details of the gas passages extending throughit;

FIG. 3 a schematically illustrated variant of the arrangement accordingto FIG. 1 for simultaneous filling of several metering containers withfilling conduits that are adjustable elastically with respect toimmersion depth;

FIG. 4 a variant of the arrangement according to FIG. 3 with acontinuously supplied distribution conduit for the different fillingconduits;

FIG. 5 a schematic illustration of an embodiment with a filling conduitthat passes slidably through the retaining device for effecting thefilling level;

FIG. 6 an embodiment with a pressing plate that covers completely themetering container and is air-permeable;

FIG. 7 an embodiment with several filling conduits per meteringcontainer;

FIG. 8 in a schematic detail view a filling conduit with a valveelement;

FIG. 9 a variant of the filling conduit with lateral supply openings;

FIG. 10 an embodiment of the invention with a metering containerembodied as a metering chamber for filling a separate storage container;

FIG. 11 a detail variant of the embodiment according to FIG. 10 with ametering chamber that is adjustable with respect to its volume by meansof a piston;

FIG. 12 a further variant of the arrangement according to FIG. 10 with ametering chamber that is pivotable into an upside down position forfilling the storage container.

FIG. 1 shows in schematic longitudinal section illustration a fillingdevice 1 according to the invention for volumetric metering of powder 2.The powder 2 in the illustrated embodiment is a powdery pharmaceuticalwhose grain size is in the range of approximately 5 micrometers or evensmaller.

The filling device 1 comprises a funnel-shaped supply container 23 inwhich a supply of powder 2 is provided. Moreover, the filling device 1comprises an air-permeable flat retaining device 10 that is howeverimpermeable to the powder 2, as well as a filling conduit 11 that at itsupper end opens into the supply container 23 and that in the area of itsopposed lower end passes through the retaining device 10. Further partsof the filling device 1 include a pressing frame 14 as well as a chamber16 that is open toward the retaining device 10 but otherwise is closedand has a connection to a vacuum source 17 and an overpressure source18, respectively.

The illustrated arrangement is provided for simultaneouslyvolumetrically metering a powder 2 and for filling a metering container3. The metering container 3 in the illustrated embodiment is a storagecontainer 19 provided for a later sealing process that, for thispurpose, is typically embodied as a blister package. The meteringcontainer 3 has an interior 5 provided for receiving the powder 2, afill opening 6 open to one side, as well as a rim 8 surrounding the fillopening 6.

The flat retaining device 10 can be a screen, a grid or the like and inthe illustrated embodiment, in accordance with the schematiccross-sectional illustration of FIG. 2, is embodied as a diaphragm 12with gas passages 12 that pass transversely through the diaphragm 12 andare separated from one another. The thickness of the diaphragm 12 in theillustrated embodiment is approximately 20 μm. However, deviatingthicknesses may be expedient. The diameter of the individual gaspassages, depending on the grain size of the powder 2 to be processed,is in a range of inclusive 0.4 μm to inclusive 1.0 μm. As needed,deviating sizes may be expedient.

The diaphragm 12 is comprised of an elastic plastic film that is elastictransverse to its plane of extension and into which gas passages 13 areetched. The gas passages 13 do not extend exactly at a right angle tothe surface of the diaphragm 12 but have scattered angles relativethereto. However, no gas passages 13 are provided that extend within theplane of the diaphragm 12. Also, the individual gas passages 13 have nofluidic communication relative to one another. In this way, it isensured that a gas exchange can take place only between the two faces ofthe diaphragm 12 but not in the direction of the plane or face of thediaphragm 12.

As a result of manufacturing technology it may happen that theindividual gas passages 13 sporadically and to a minimal extentpenetrate one another or contact one another so that in an exceptionalsituation individual gas passages 13 are communicating fluidically withone another. The separation of the individual gas passages 13 from oneanother in the context of the present invention means only that suchfluidically conducting connections occur only sporadically or to aminimal degree but not to a significant extent so that a noticeabletransverse flow within the plane or surface of the diaphragm 12 cannotbe produced.

When filling the metering container 3 according to FIG. 1, the retainingdevice 10 covers the fill opening 6 as well as the circumferentiallyextending rim 8 of the metering container 3. The pressing frame 14 hasan inner contour that at least approximately coincides exactly with thecontour of the fill opening 6. The retaining device 10 is pressedcircumferentially by means of the elastic pressing frame 14,contour-flush and seal-tightly, onto the rim 8 of the metering container3. By means of the contour-flush arrangement of the pressing frame 14relative to the fill opening 6 the retaining device 10 can be flowedthrough by air in the direction of arrows 22 across the entire surfacearea of the fill opening 6 without the powder 2 being able to penetratethrough the retaining device 10. As a result of the seal-tight contactcaused by the elastic pressing frame 14 and the lack of possibility fortransverse flow within the plane of the retaining device 10, externalinfluences from outside of the metering container 3 and the chamber 16are precluded.

During the filling process according to FIG. 1 the filling conduit 11passing through the retaining device 10 opens in the interior 5 of themetering container 3. In this connection, the chamber 16 restsseal-tightly on the retaining device 10 on the side of the retainingdevice 10 facing away from the metering container with interposition ofthe pressing frame 14. The chamber 16 is only open toward the retainingdevice 10. In other respects, with the exception of the connections tothe vacuum source 17 and the overpressure source 18, it is closed sothat the interior of the chamber 16 can be loaded, as needed, withvacuum or overpressure. In this way, means are formed for generating apressure differential between the two sides of the flat retaining device10.

In usual operation in the area of the supply container 23 atmosphericpressure exists while during the course of the filling process thechamber 16 is connected to the vacuum source 17. As a result of thegenerated pressure differential an air flow is created that inaccordance with arrows 22 flows from the interior 5 of the meteringcontainer 3 through the retaining device 10 into the interior of thechamber 16. This air flow is sucked in from the supply container 23through the filling conduit 11 wherein the powder 2 from the supplycontainer 22 is entrained through the filling conduit 11 in accordancewith arrows 21 into the interior 5 of the metering container 3. Theaforementioned diameter of the gas passages 13 (FIG. 2) has the effectthat the sucked-in air in accordance with arrows 22 can be suckedthrough the retaining device 10 but the particles of the powder 2 areretained at the retaining device 10. Since the retaining device 10 isflowed through across the entire surface of the fill opening 6, thepowder 2 is distributed in the entire interior 5 of the meteringcontainer 3 until a gap-free filling of the interior 5 up to the rim isachieved.

In practical operation it cannot be excluded that individual passages 13(FIG. 2) will become clogged with powder grains. After completed fillingof the interior 5 the connection to the overpressure source 17 can beinterrupted and instead the connection to the vacuum source 18 can beproduced. In this way, the pressure differential is reversed. A briefflow through the retaining device 10 opposite to the arrows 22 takesplace which leads to cleaning of the gas passages 13.

After completion of the aforementioned process, the interior of thechamber 16 is loaded with atmospheric pressure so that the meteringdevice 3 can be removed from the retaining device 10. Since the latterduring the filling process has been resting seal-tightly on the rim 8 ofthe metering container 3, the rim 8 is completely free of contaminationby the powder 2. Only in the interior 5 the powder 2 is present whichhas been metered precisely by means the volume of the interior.Immediately after removal of the metering container 3 from the retainingdevice 10 the circumferential rim 8 can be sealed with a sealing film bygluing or welding. A sealed storage container 19 is formed which,without further intermediate steps, is completed for storage andutilization by the consumer.

Depending on the size of the metering container 3 and the fine-poreconfiguration of the retaining device 10, almost any individualquantities of powder 2 in almost any grain size can be filled in andmetered. In particular, the filling device 1 and the correspondingmethod are suitable to meter and fill in very small powder quantities inparticular in the medical field. For example, in pulmonary applicationsthe individual quantities may be in a range of inclusive 0.3 mg to 50mg. Typically, they are within a range of inclusive 2 mg to inclusive 25mg. In case of a powdery pharmaceutical for transdermal applications,the individual quantities are typically in a range of inclusive 0.2 mgto inclusive 5 mg. The volume of the interior 5 of the individualmetering container 3 is within a range of inclusive 0.1 μl to inclusive100 μl.

FIG. 3 shows in a schematic view a further embodiment of the fillingdevice 1 according to FIG. 1 in which the retaining device 10 has alarge surface area and covers continuously several metering containers3. For each metering container 3 a filling conduit 11 is provided,respectively, that at a suitable location passes through the retainingdevice 10 and opens in the interior 5 of the individual meteringcontainer 3, respectively. All filling conduits 11, as indicated byarrows 24, are supplied from a common supply container 23 with thepowder 2.

The retaining device 10 is embodied so as to be elastically deformabletransverse to its surface wherein a first deformation end position isindicated with solid lines and a second deformation end position isillustrated with dashed lines. The individual filling conduits 11 eachare fixedly connected to the retaining device. By utilization of theelastic yielding action of the retaining device 10, the individualfilling conduits 11 together with the section of the retaining device 10connected thereto can be lifted or lowered in accordance with doublearrow 25. Depending on the height adjustment of the respective fillingconduit 11, it projects together with the section of the retainingdevice 10 connected thereto more or less far into the interior 5 of therespective metering container 3. In this way, a volume adaptation of theinterior 5 is provided. Since a complete filling of the interior 5 withthe powder 2 is provided, also a filling level control of the powder 2in the interior 5 is realized in this way. Metering of the powderquantity to be filled into the respective metering container 3 can becorrected or adjusted in this way.

FIG. 4 shows another variant of the arrangement according to FIG. 3 inwhich the individual filling conduits 11 are supplied from a commondistribution line 26 with the powder 2. Instead of a supply from asupply container 23 in accordance with FIG. 3, according to FIG. 4 it isprovided that the powder 2 in accordance with arrow 27 is continuouslyconveyed in circulation through the distribution line 26 so thatcontinuous uniform supply conditions are present in the distributionline 26 and thus also in the individual filling conduits 11. In regardto other features and reference numerals the arrangement according toFIGS. 3 and 4 coincide with one another as well as with the arrangementaccording to FIGS. 1 and 2.

Further embodiments of the invention are illustrated in FIGS. 5 through12. Here it also applies that the features and reference numeralscoincide with one another and with the afore described embodiments, ifnot noted otherwise. As an alternative to the embodiment of FIGS. 3 and4, in the embodiment according to FIG. 5 it is provided that the fillingconduit 11 is guided through the retaining device 10 so as to beslidable in its longitudinal direction, as its illustrated by doublearrow 28 as well as by the end positions of the filling conduits 11indicated by dashed lines. In analogy to the illustration according toFIG. 3, a filling level control of the powder 2 in the interior 5 of themetering container 3 is realized in that the filling conduit 11 ispushed through the retaining device 10 more or less deeply into theinterior 5 or removed therefrom. The retaining device 10 itself remainsin place without carrying out any noticeable deformation.

In the embodiment according to FIG. 6, instead of the elastic pressingframe 14 an in particular elastic pressing plate 15 is provided that ispenetrated by gas passages distributed across its surface area andtherefore is permeable. The flat pressing plate 15 covers one or severalmetering containers 3 including the correlated fill openings 6 and rims8. In this connection, the respective retaining device 10 is pressedcircumferentially against each rim 8 of the metering container 3 so thata sealing action of the interior 5 is provided. The gas passages thatextend through the pressing plate 15 are comparable to the gas passages13 according to FIG. 4 so that here also no significant transverse flowwithin the plane of the pressing plate 15 can be generated. Nonetheless,the air-permeable pressing plate 15 enables the generation of a pressuredifferential and flow through the retaining device 10, as explained inconnection with FIG. 1. The flat configuration of the pressing plate 15is independent of any format, i.e., is not tied to the contour of theindividual metering containers 3. Without adaptation of the retainingdevice 10 and the pressing plate 15, different types of meteringcontainers 3 with any contour of its fill opening 6 can be filled.

FIG. 7 shows a schematic illustration of a further embodiment of theinvention in which each individual metering container 3 has correlatedtherewith at least two or even more individual filling conduits 11. Theindividual filling conduits 11 pass in the afore described way throughthe retaining device 10 and open at different locations of theindividual metering container 3 in its interior 5. This enables thegap-free filling of the interior 5 flush with the rim even for irregularcontours of the fill openings 6, in particular when individual fillingconduits 11 are arranged in the corner areas of the respective meteringcontainer 3.

FIG. 8 shows a detail view of a possible embodiment of the fillingconduit 11 according to a preceding embodiment in the area of its endfacing the container. The filling conduit 11 has at its end face that isfacing the container a supply opening 32 for the powder 2 that, asneeded, can be closed by a schematically illustrated valve element 29.In the illustrated embodiment, for this purpose a pull rod 30 isprovided that is connected to the valve element 29 and by means of whichthe valve element, in accordance with double arrow 31, can be pulledseal-tightly into the supply opening 32. Sealing of the supply opening32 by means of the valve element 29 can be done as needed, for example,when in accordance with the illustration of FIG. 1, the retaining device10 is blown out with overpressure in the chamber 16. In this case, thevalve element 29 prevents that the powder 2 is blown through the fillingconduit 11 in reverse direction. Instead of actuation by the pull rod 30it may also be expedient to provide an automatic actuation of the valveelement 29.

Alternatively or in addition to the embodiments according to FIGS. 1through 8, also an embodiment of the fill opening 11 in accordance withthe illustration of FIG. 9 may be expedient in which one or severalsupply openings 32 are distributed on the circumference of the end ofthe filling conduit 11 projecting into the interior 5 of the meteringcontainer 3. For certain shapes of the metering container 3, this cancontribute to improved filling of the interior 5 with the powder 2.

The FIGS. 10 through 12 show in schematic illustration a further variantof the filling device 1 and of the correlated method wherein themetering container 3 formed as a storage container 19 is not directlyfilled but filled by means of an additional metering container 4 that isembodied as a metering chamber 20. In analogy to the metering container3 according to FIGS. 1 through 9, the metering container 4 has a fillopening 7 and a circumferentially extending rim 9 wherein the fillopening 7 and the circumferentially extending rim 9 are covered, asdescribed above, by the flat retaining device 10. In deviation from themetering container 3, the metering container 4 embodied as a meteringchamber 20 has at its bottom side an opening that is closed by a closureplate 33. With otherwise identical features and reference numerals, themetering container 4 is filled as described above wherein the powder 2is metered volumetrically in accordance with the volume of its interior5. After completed metering action, the closure plate 33, in accordancewith double arrow 34, can be pushed to the side so that thevolumetrically metered powder 2 can drop out of the metering chamber 20into the metering container 3 arranged underneath that is embodied as astorage container 19.

Alternatively or in addition to the closure plate 33 of FIG. 10, apiston 35 can be provided in accordance with the illustration of FIG. 11that, in accordance with double arrow 36, can be pushed more or less farinto the interior 5 of the metering container 4. In this way, a volumeadaptation of the interior 5 can be provided so that the volume of thepowder 2 to be metered can be adjusted in the metering chamber 20.

A further embodiment is illustrated in FIG. 12. The metering container 4embodied as a metering chamber 20 corresponds together with theremainder of the filling device 1 substantially to the embodiment ofFIGS. 1 to 9 and is filled analogously with the powder 2. Aftercompleted filling, the metering chamber 20 is turned upside-down so thatthe powder 2 contained therein in accordance with arrow 37 drops intothe metering container 3 underneath that is embodied as a storagecontainer 19.

1-12. (canceled)
 13. A filling device for volumetric metering of powder,the filling device comprising: a metering container with an interior andwith a fill opening communicating with said interior and surroundedcircumferentially by a rim; an air-permeable flat retaining device thatis impermeable for the powder, wherein said retaining device coversduring filling of said metering container said fill opening and saidrim; a filling conduit passing through said retaining device and openinginto said interior when filling the powder into said metering container;pressure generating means that generate a pressure differential at saidretaining device.
 14. The filling device according to claim 13, whereinsaid retaining device is a diaphragm with gas passages that extendtransversely to a face of said retaining device through said diaphragmand that are separated from one another.
 15. The filling deviceaccording to claim 13, wherein said retaining device is elasticallydeformable transverse to a face thereof so as to provide an elasticyielding action, wherein said filling conduit is fixedly connected tosaid retaining device, and wherein a filling level control for thepowder in said interior of said metering container is provided bylifting or lowering said filling conduit by utilizing said elasticyielding action of said retaining device.
 16. The filling deviceaccording to claim 13, wherein said filling conduit is guided throughsaid retaining device so as to be slidable in a longitudinal directionof said filling conduit, wherein a filling level control for the powderin said interior of said metering container is provided by sliding in orpulling out said filling conduit relative to said metering container.17. The filling device according to claim 13, wherein said retainingdevice covers continuously several of said metering container.
 18. Thefilling device according to claim 13, wherein several of said fillingconduit are provided for each one of said metering container.
 19. Thefilling device according to claim 13, furthercomprising a pressingframe, wherein said retaining device is pressed circumferentiallyagainst said rim by said pressing frame that is embodied to becontour-flush with said rim.
 20. The filling device according to claim19, wherein said pressing frame is elastic.
 21. The filling deviceaccording to claim 13, further comprising a flat, air-permeable pressingplate, wherein said retaining device is pressed circumferentiallyagainst said rim by said pressing plate that covers said rim and saidfill opening.
 22. The filling device according to claim 21, wherein saidpressing plate is elastic.
 23. The filling device according to claim 13,wherein said pressure generating means comprises a chamber arranged on aside of said retaining device that is facing away from said meteringcontainer, wherein said chamber is open toward said retaining device butotherwise is closed, wherein said chamber has a connector to a vacuumsource.
 24. The filling device according to claim 23, wherein saidchamber has a connector to an overpressure source.
 25. The fillingdevice according to claim 13, wherein said metering container is astorage container to be sealed later.
 26. The filling device accordingto claim 13, wherein said metering container is a metering chamberconfigured to fill a storage container.